Crane 1.6 roller rockers on a TPI L98....

I installed a set of Crane's "Gold Race" 1.6 rockers on my L98 about 2 weeks ago. Since I was no longer using them on my 4th gen LT1, I figured it would be a quick easy way to pick up some HP on my IROC.

In order to save on the down time, I used my old LT1 valve covers since I wanted to paint them before hand. The only difference between the LT1 covers and the L98 is that the LT1's are "notched" on the passenger side to make room for the alternator. Other than that, the L98/LT1 covers are the same.

I have no issues with clearance at all.

After finally being able to test drive the car, the power increase provided by the 1.6 rocker's was immediately apparent. For starters, the car seems to run a lot smoother. Not just driving around town, but at idle as well. Don't exactly know the reason for this, but it was definitely an unexpected bonus. On top of that, it pulls a lot harder then it did before, especially from 3500+. It was definitely worth the 2 hours I spent installing them..

I put the car on the dyno the next day and with nothing more than those rockers and a full exhaust upgrade (not even a full 3" exhaust at that and I'm still running a cat)), I put 212hp and 290 at the wheels. All else is 100% stock (minus the replacement air filters)

I'd say 1.6 roller rockers are a relatively cheap and affordable mod for some quick and easy HP. A definite "seat of the pants" improvement for sure. :biggrin:

i was looking to do the same for some added power without ripping into the short block.....this is exactly wat i wanted to hear. wat is the part number for the rockers u have there? im having trouble finding anything on summit that will fit our car....idk why? i def want 1.6 rollers but i dont want to spend a butt load maybe like 100-170$. the rockers that fit our heads are they self aligning?

how much u think u gained from the rockers? i kno u did the exhaust and is that a complete including 3" after cat as well? supposedly u get like 10hp with a rocker upgrade. 212hp and 290 at the wheels...i wonder wat that equates out to at the engine, since ours is stock at 225hp and 330/340 tq

new BLACK paint job all body work done by me filled in antenna hole for sleek look as well as holes in trunk lid NO DECALSnew SLP 5 spoke 17x8 hyper black rims rapped in nitto's ZR 245/45/R17 all around

i was looking to do the same for some added power without ripping into the short block.....this is exactly wat i wanted to hear. wat is the part number for the rockers u have there? im having trouble finding anything on summit that will fit our car....idk why? i def want 1.6 rollers but i dont want to spend a butt load maybe like 100-170$. the rockers that fit our heads are they self aligning?

how much u think u gained from the rockers? i kno u did the exhaust and is that a complete including 3" after cat as well? supposedly u get like 10hp with a rocker upgrade. 212hp and 290 at the wheels...i wonder wat that equates out to at the engine, since ours is stock at 225hp and 330/340 tq

It's been a couple years since I first purchased these for my 4th gen LT1 Formula, but I'm pretty sure the part no. was 270-10758-16. They go for about $320US give or take. They're self-aligning by the way, and even though the product description says "LT1/LT4" they'll also fit our TPI cars without issue.

I'd say these were worth about 10-15hp throughout the entire RPM range from 2500+ Yes, I have an after market exhaust, (Dynomax) but it's not actually a 3" system. It's 2.75" (don't ask me why) but with just the headers, cat-back and the rockers, yes, 212hp and 290 at the wheels. Considering my cat-back isn't even a 3"diameter, those numbers are pretty good, still, and show just how much of an improvement the rockers really are.

Generally, the rule of thumb is, you lose 20% of your power through an automatic equipped car. My guess is the car (with just those 3 mods) puts out aprox. 265hp and 360lb of torque at the fly wheel.

In '88 these cars were rated at 230/330 so that's aprox 35hp and 30 lb torque increase from headers, roller rockers, and 2.75" exhaust. Not too shabby.

Also keep in mind this is a 190,000km motor.....

The Crane's are overly expensive though, and I'm sure a lot of that is paying for the name alone. You would get the same results I did with a different brand roller rocker...

i was thinking about profroms extruded aluminum from summit, part # PRO-66915...the only prob is that it doesnt say for centerbolt valve covers. same part # for jegs with a C at the end says centerbolt valve covers. although the summit has a PRO-66915C is doesnt give me any info about the rockers. the ones i ordered though do say 3/8 stud, self aligning, narrow body, polylock, fits 305 and 350, fits engines 87-2000 and i believe that all engines after 87 recieved centerbolt valve covers...

190,000km motor....wat does that equate out to in miles lol i got 128,000 miles on the clock with out ripping the heads, pan, or intake baseplate off at all. all stock long block(i dont count the runners or plenum in long block) sounds like you got me beat though.

new BLACK paint job all body work done by me filled in antenna hole for sleek look as well as holes in trunk lid NO DECALSnew SLP 5 spoke 17x8 hyper black rims rapped in nitto's ZR 245/45/R17 all around

just make sure you look for narrow body rockers so they fit under centerbolt valve covers and self aligning or SA unless you wanna run guide plates. look on ls1tech dot com and some other forums i got my set or 1.6 RR for 75 shipped and they are the silver ones meade by crane for the lt1 hotcam kit good deals to be found out there

i was looking to do the same for some added power without ripping into the short block.....this is exactly wat i wanted to hear. wat is the part number for the rockers u have there? im having trouble finding anything on summit that will fit our car....idk why? i def want 1.6 rollers but i dont want to spend a butt load maybe like 100-170$. the rockers that fit our heads are they self aligning?

how much u think u gained from the rockers? i kno u did the exhaust and is that a complete including 3" after cat as well? supposedly u get like 10hp with a rocker upgrade. 212hp and 290 at the wheels...i wonder wat that equates out to at the engine, since ours is stock at 225hp and 330/340 tq

if ya'l are talking about the 5.7 litre 350 tpi engine then it comes stock with 245 hp and 345 ft lbs of tourque...atleast mine did....i have a 91 formula and i checked out the stats sheet on a website that tells me hp ratings and gears...etc. also..can i run a 3" exhaust even if i dont have headers yet....shuld i leave the cats or take them out...they have some weird looking metal tube running into them and im not sure what it is yet....i dont think it is the o2 sensor but it could be on the other end of the tube that i cant see....

yea we are but ours is the 87-88 model and are only rated at 225hp and 330 torque. yea u can run a 3 inch exhaust like in the form of a catback, u just need a conversion peice to fit the y pipe to a 3 inch cat, or a peice to fit the cat to the 3 inch catback, the weird metal tubes that are running to the cats are scavanger tubes that route excess gases back into the exhaust. the 02 sensors look like sensors with a wire comint out of them and are located usually stock on the exhaust manifold collector. i wouldnt touch the cats unless u upgrade with headers, ypipe and cat back then i might do high flow cats....but then u wont pass emissons if u take them out

new BLACK paint job all body work done by me filled in antenna hole for sleek look as well as holes in trunk lid NO DECALSnew SLP 5 spoke 17x8 hyper black rims rapped in nitto's ZR 245/45/R17 all around

yea we are but ours is the 87-88 model and are only rated at 225hp and 330 torque. yea u can run a 3 inch exhaust like in the form of a catback, u just need a conversion peice to fit the y pipe to a 3 inch cat, or a peice to fit the cat to the 3 inch catback, the weird metal tubes that are running to the cats are scavanger tubes that route excess gases back into the exhaust. the 02 sensors look like sensors with a wire comint out of them and are located usually stock on the exhaust manifold collector. i wouldnt touch the cats unless u upgrade with headers, ypipe and cat back then i might do high flow cats....but then u wont pass emissons if u take them out

quick queston...how can u produce 212 hp on a dyno but then get 290 hp at the wheels?? it makes no sense to me....